Perforated workpieces are required for many technical applications, particularly as economical optical or mechanical filters having pore diameters in the .mu.m and sub-.mu.m range. For example, such applications are isoporous membranes, back-rinsable filters, laminizers, catalyst carriers, electrodes for batteries and field cells, nozzle plates, tube gratings or filters for electromagnetic waves, such as, for example, light or microwaves.
A known method for manufacturing such filters is a so-called LIGA technique, wherein LIGA stands for Lithography, Galvanik (a German word for electroplating) and Abformung (a German word for shaping). In the LIGA technique which, for example, is known from E. W. Becker et al, Microelectronic Engineering, Vol. 4 (1986), pages 35ff, a thick photoresist layer is structured with the assistance of a synchrotron radiation. Subsequently, the structures are transferred into the filter by electroforming and shaping techniques with plastics. Minimum structural widths of 2 .mu.m can be achieved with the LIGA technique. However, no structuring is possible in a dimension extending parallel to the throughput direction through the filter. The required employment of synchrotron radiation makes this method extremely expensive.